Origin: The cherimoya is believed to be native to the inter-andean
valleys of Ecuador, Colombia and Peru. Seeds from Mexico were planted in
California (Carpinteria) in 1871.

Adaptation: The cherimoya is subtropical or mild-temperate and will
tolerate light frosts. Young growing tips are killed at 29° F and and
mature trees are killed or severely injured at 25° F. If cherimoyas do
not receive enough chilling, the trees will go dormant slowly and then
experience delayed foliation. The amount of chilling needed is estimated to
be between 50 and 100 hours. The tree grows well in the coastal and foothill
areas of southern California, doing best at a slight elevation, 3 to 15 miles
from ocean. It is worth attempting in sunny, south-facing, nearly frost-free
locations from San Francisco Bay Area to Lompoc, and may survive to fruit in
a very few protected Central Valley foothill locations from Chico to Arvin.
Resentful of the excessive dry heat of the interior, it is not for the desert.
Cherimoyas are not recommended for container culture.

DESCRIPTION

Growth Habit: The cherimoya is a fairly fairly dense, fast-growing,
evergreen tree, briefly deciduous in California from February through April.
The tree can reach 30 feet or more, but is fairly easily restrained. Young
trees "harp," forming opposite branches as a natural espalier. These can be
trained against a surface, or pruned off to form a regular free-standing
trunk. Growth is in one long flush, beginning in April. The roots commence
as taproot, but the slow-growing root system is rather weak, superficial, and
ungreedy. Young plants need staking.

Foliage: The attractive leaves are single and alternate, 2 to 8 inches
long and up to 4 inches wide. They are dark green on top and velvety green on
the bottom, with prominent veins. New growth is recurved, like a fiddle-neck.
Axillary buds are hidden beneath fleshy leaf petioles.

Flowers: The fragrant flowers are borne solitary or in groups of 2 or 3
on short, hairy stalks along the branches. They appear with new growth flushes,
continuing as new growth proceeds and on old wood until midsummer. The
flowers are made up of three fleshy, greenish-brown, oblong, downy outer
petals and three smaller, pinkish inner petals. They are perfect but
dichogamous, lasting approximately two days, and opening in two stages,
first as female flowers for approximately 36 hours. and later as male
flowers. The flower has a declining receptivity to pollen during the female
stage and is unlikely to be pollinated by its own pollen in the male stage.

Fruits: The compound fruit is conical or somewhat heart-shaped, 4
to 8 inches long and up to 4 inches in width, weighing on the average 5-1/2
to 18 ounces, but the largest fruits may reach 5 pounds in weight. The skin,
thin or thick, may be smooth with fingerprint-like markings or covered with
conical or rounded protuberances. The sweet, juicy, white flesh is melting,
subacid and very fragrant. The fruit is of a primitive form with spirally
arranged carpels, resembling a raspberry. Each segment of flesh surrounds a
single hard black bean-like seed. The fruit size is generally proportional
to the number of seeds within. They ripen October to May.

CULTURE

Location: Cherimoyas prefer a sunny exposure, buoyant marine air and
cool nights. In southern California do not plant where heat collects on
barren hillside or against a wall, since the leaves and fruit may sunburn
badly. In the north, do the opposite: plant against a south facing wall to
collect heat and encourage early bud-break and fruit ripening. The trees
need protection from constant ocean or Santa Ana winds which may damage
them and interfere with pollination and fruit set.

Soil: The cherimoya performs well on a wide range of soil types from
light to heavy, but seems to do best on a well-drained, medium soil of
moderate fertility. The optimum pH ranges from 6.5 to 7.6.

Irrigation: Cherimoyas need plenty of moisture while they are growing
actively, but should not be watered when they are dormant. The trees are
susceptible to root rot in soggy soils, especially in cool weather. Commence
deep watering biweekly in April. Drip irrigation is also an excellent way to
supply water. It is best to avoid poor water to prevent salt build-up.
Drought-stressed trees will drop their leaves, exposing the fruit to sunburn.

Fertilization: Cherimoyas should be fertilized on a regular basis.
Apply a balanced fertilizer, such as 8-8-8 NPK, in midwinter, then every
three months. Increase the amount of fertilizer each year until the trees
begin to bear fruit. Mature trees require an annual application of 4 ounces
of actual nitrogen per inch of trunk diameter. Cherimoyas also respond to
organic amendments. It should be kept in mind that yellow leaves may mean
that the soil too dry or the weather too cold, not always a need for
fertilizer.

Pruning: Cherimoyas have rather brittle wood. Prune during the dormant
period to develop strong branches that can support the heavy fruit. Train
the tree to two scaffold branches at 2 feet of trunk, pruning them to a
2 foot length. Save only the strongest single shoots, preferably those at 60
to 90 degree angle, and remove the others. In the following years, remove
two-thirds of the previous year's growth, leaving six or seven good buds, at
time of new growth. This will keep fruiting wood within reach of the ground.
Thin out crossing branches.

Frost Protection: Young trees are very frost sensitive. Wrap the
trunk and scaffold with sponge foam for protection, or cover the entire tree.
In cooler areas plant next to a south-facing wall or under the eaves to trap
house heat.

Pollination: Since natural pollinators are not present in California, the
flowers must be pollinated by hand. This is best done in mid-season of bloom,
over a period of two to three months. In early evening, collect in a small
bottle the anthers and pollen from the interior of fully open male flowers
with a #2 or #3 artists brush. Anthers will be tan colored and the white
pollen falling from them will be obvious. The pollen has its highest
viability at the time it is shed and declines significantly with time.
Immediately apply freshly collected pollen with a small brush to the flowers
in partially open, female stage. If no female stage flowers are available,
pollen may be saved in the sealed container under refrigeration overnight.
Pollen may then be applied to female stage flowers in the morning.
In large scale operations the pollen may be mixed with inert Lycopodium
spores, PVC, starch or talc powder and applied with aspirator-type Japanese
apple-pollinators, to save time and pollen. Pollinate every two or three
days, and only flowers easily reached inside the tree, to avoid sunburned and
wind-damaged fruit. If pollination efforts are quite
successful, it may be necessary to thin the fruit. Too much fruit may result
in small size and adversely effect future yields.

Propagation: Since there are no recognized rootstocks for cherimoyas,
seedlings are universally utilized. Seeds from the White cultivar (Dr.
White) are thought by some to produce superior rootstocks, however there does
not appear to be a great deal of objective data to support this position.
Seeds remain viable for two to three years if kept dry and protected from
weevil and fungi. With 70° F bottom heat, seed will germinate in about
21 days, but will require about 40 days under normal ambient growing
conditions.
Seedlings should be transplanted to deep containers (approximately 18") when
they are 3" tall to promote development of the tap root. In frost-free areas,
it is recommended that seedlings for spring grafting be planted in their
ultimate location in the fall and grafted in the ground the following spring.

Grafting is most successful in January through May provided previous years
leaves have not been shed from the potential scionwood. During this period
no scion preparation is required other than removal of leaves. All normal
grafting techniques appear to be equally successful. However in topworking,
nurse branches are desirable if not essential for success. To
bud, collect budwood in July store refrigerated for 10 days in plastic.
Petioles will drop exposing dormant buds. Bud at once using chip bud
technique and wrap well against dehydration. Grafted plants will bear in two
to three years.

Pests and Diseases: Mealybugs and snails are the main pests of
cherimoyas. Keep ducks or apply copper strips to the trunks for control of snails.
Mealybugs are brought by ants which can be controlled to some extent by
maintaining fresh Tanglefoot on masking tape around the trunk. The masking
tape is important to prevent damage to the tree. Skirt the tree to prevent
ant access from the ground or weeds. No chemicals are registered for use on
Cherimoyas.

Cherimoyas are susceptible to Armillaria (Oak Root Fungus) and Verticillium.
Do not plant in old vegetable gardens, or near tomatoes, eggplant or asters.
Crown rot can kill trees damaged by frost or growing in saturated soil, as
well as from trunks hit by frequent, superficial lawn sprinkling.

Harvest: The fruit turns a pale green or creamy yellow color as they
reach maturity. Color change is not marked in cool weather. They should be
picked when still firm and allowed to soften at room temperature. Ripe
fruit will give to soft pressure. Overripe fruit will be dark brown. Fruit
left on the tree too long will usually crack or split and begin to decay.
The fruit should be clipped rather than pulled from the tree. Cut the stem
close to the fruit so it won't puncture other fruit during storage.

Store mature fruit above 55° F to prevent chilling injury to the skin and
flesh. Ripe fruit will deteriorate quickly but can be stored at temperatures
lower than 55° F for short periods. Ripe cherimoyas can be frozen and eaten
like ice cream. Cherimoyas are best served chilled, cut in half or quartered
and eaten with a spoon. The fruit can also be juiced or used to make
delicious sorbets or milkshakes.

Commercial Potential: Though unusual in appearance, cherimoyas are readily
accepted by western tastes and has become a favorite tropical fruit. Demand
greatly exceeds supply in all U.S. markets as most fruit never leaves
California, the only producing state. The fruit commands high wholesale and
retail prices, but costs are high and major crop losses from frost and fruit
splitting are an ever present possibility. The major labor costs are pruning,
pollination, ant control and irrigation.

Believed to be from a group of scions imported from Mexico in the 1930's by a
Mr. Knight of Orange. Dr. H. F. Pierce planted a grove in Goleta in that
period made up largely of trees produced by Knight. This cultivar was Dr.
Pierce's favorite and was named "Pierce" by him. Tree is vigorous with large
dark green leaves. Fruit is medium sized elongated conically shaped with very
smooth skin and a high sugar content.

Sabor

Origin James Neitzel, San Diego, Calif., 1979. Sibling of "Big
Sister". Fruit mammillated, varies in size, not usually large. Among the best
in flavor.